Grand Canyon Natural History Association, 1984. Paperback. 141pp. Quarto [28 cm] Tan and black printed softcover. Very good. The spine is faded. There is a faint name in erased pencil on the front cover, and there is an old price sticker on the rear cover. A handful of pages have minor underlining or marginalia in pencil. Item #35337
Grand Canyon Natural History Association Monograph Number 6. with contributions by Donald P. Elston, Stanley J. Olsen, Richard H. Hevly, C. W. Ferguson, and others.